Suppose that I have a market research survey with the question "What brand of television are you planning on buying" and then also have a choice that is "I don't plan on buying a television." Respondents may choose more than one brand, but they may not make any other choices if they select that they do not plan on buying a television.
If I wanted to do an analysis of television brands among only those people who said they were going to buy a television, can I remove all of the respondents that said they would not buy a television, then recalculate the proportions for each brand with the new base number of observations?
If this skews the demographic distribution of my sample, is that okay? (e.g. the full sample has 30% Caucasians and 10% Asians, but the sample of people who say they will buy televisions is 30% Asians and 10% Caucasians. It seems like this should be okay, since we would not expect the two populations (TV buyers and people in general) to be the same.